This may not completely work.. As there are about 600000 paragraphs and trying to eliminate it that way may not be very efficient. ( I havent tested it)
And about 200 keywords. ( these are the maximum count we are considering )
Will look if brute force or spanning tree can be used.
Thanks all for the help and also i understand the homework part however my comment was posted only for the part where somebody without knowing or assuming made some unnecessary comments.